Air Cleaners & Allergy Control
What size air cleaner do you need?
Rounding out our list of Top 5 Allergy Control
Products is the HEPA air cleaner.
It is not necessary to have an air cleaner in every room of your house. While it
would be nice if all the air in your house could be filtered, you will get the
biggest benefit from having an air cleaner in your bedroom. This is because you
spend more time in your bedroom than any other room in your house. It may not
seem that way to you, but that is because you are mostly asleep when you are in
your bedroom. You might sleep 8 hours a night every night. You rarely spend 8
hours straight in your home kitchen! Want to breathe clean air? Get a HEPA air
two most common types of air cleaners for the home are ionizers and air filters.
We don’t recommend ionizers because most of them produce ozone. Ozone in large
amounts can be toxic and even in small amounts can irritate the respiratory
system. We do recommend HEPA filters.
HEPA is an acronym for High Efficiency Particulate Air. It is a measurement that
was developed during work on the first atomic bomb and means that 99.97% of
particles as small as 0.3 microns are arrested by the filter. This particle size
includes lung damaging particles as well as the particles in common household
dust and other indoor allergens.
A HEPA filter is only as good as the motor that delivers the dirty air to the
filter. If the particles never make it to the filter, then the filter can’t stop
the particles. It is just common sense.
It is very important that no matter what brand
of air cleaner you choose; you choose the right size for your room. You can
have a machine that is too large for the room and just run it on a lower speed
with no problem. However, if your machine is too small for the room no matter
what speed to which you have it set, it will not be able to do the job
effectively. If it isn’t going to work, then why have it?
When you start looking at air cleaners it is very easy to be confused. Some
machines have a CADR (clean air delivery rate) rating; others tell you they can
clean a certain square footage of space. This is also confusing because when you
clean the air in a room you are cleaning the volume of air (3 dimensions) not
the surface (2 dimensions) of the room.
The easiest way to determine if a machine is the proper size is to calculate how
many air exchanges an hour the machine can make. If a machine can make 6 to 8
air exchanges an hour, it can keep the air clean.
To calculate air exchanges, first you need to know the volume of air in the
room. This is easily calculated by multiplying the length by the width by the
ceiling height in the room. If the ceiling is slanted you can take an average
for the ceiling height. So, L x W x H = Volume of air in room. If you divide the
volume of the air in the room by the amount of air moved by the motor you will
find out how long it will take to make one air exchange.
To find out the amount of air moved by the motor, look and the machines
specifications. Somewhere in the technical data will be the amount of air moved
by the motor expressed in cubic feet per minute (cfm). This number is the amount
of air moved by the motor expressed in cubic feet of air per minute. So for a
room that is 10 x 12 with an 8 foot ceiling, the volume of the air in the room
is 960 cubic feet. (10 x 12 x 8 = 960). If you are looking at an air cleaner
that moves 200 cfm on the highest setting (like the Austin Air HealthMate
Junior) then you can divide 960 ÷ 200 = 4.8 or roughly 5 minutes for one air
exchange on high. Since there are 60 minutes in an hour, 60 ÷ 5 = 12 or 12 air
exchanges an hour.
Once you decide on the proper size machine, make sure it is actually providing
HEPA filtration. Some makers call their filters “HEPA type” or “hospital like”
filtration. This is not true HEPA. It does not capture all those small
Once you have purchased you air cleaner, place it in your bedroom, turn it on
the highest setting and close the door for a few hours. This will allow the
machine to work at its maximum level to clean the air in the room. When you are
ready to go to bed, turn the machine down to a lower setting and keep it there.
Under normal conditions, you will run the machine at a lower setting 24 hours a
day 7 days a week. You only turn the machine back to the highest setting when
you are changing the bed linens and cleaning the room. Once the room has been
dusted, vacuumed, etc you will want to leave your machine running on its highest
setting for about 2 hours with the door to the room closed. This will allow the
machine to capture all of the particles that became airborne in the process of
A high quality air cleaner should require little to no maintenance other than
dusting and an occasional filter change.
Wishing you the best of health
The Allergy Store